1. Field of the Invention
The present invention relates to a semiconductor integrated circuit device and, in particular, it relates to a semiconductor integrated circuit device that uses an output voltage boosted by a boosted-voltage power-supply circuit for an internal circuit and to a control circuit that controls the internal circuit.
2. Description of the Related Art
In recent years, semiconductor integrated circuit devices have been mounted on various portable apparatuses and their power supply voltage has been reduced. In the semiconductor integrated circuit devices driven by a low voltage, boosted-voltage power-supply circuits are used so that the semiconductor integrated circuit devices are operated by output voltages boosted by the boosted-voltage power-supply circuits.
Incidentally, for example, in a DRAM (Dynamic Random Access Memory), at power-up, a boosted-voltage power-supply circuit is activated first and, then, after the potential of the boosted-output voltage (the boosted voltage) of the boosted voltage power supply circuit reaches a specified level, a reduced-voltage power-supply circuit, using the output voltage, operates to reduce the boosted voltage and apply the reduced voltage to a control circuit so that the control circuit can perform reset operations for an internal circuit (for example, redundant operations for failed memory cells, and the like). Further, besides the DRAM, various semiconductor integrated circuit devices using the output voltage (boosted voltage) boosted by the boosted-voltage power-supply circuit for the internal circuit and for the control circuit that controls the internal circuit are provided. In this connection, in some semiconductor integrated circuit devices, the voltage that is reduced from the boosted voltage by the reduced-voltage power-supply circuit is not applied to the control circuit but the boosted voltage is applied directly.
In such semiconductor integrated circuit device (chip) using the boosted-voltage power-supply for controlling the internal reduced-voltage power-supply, for example, if any circuits using the intra-chip boosted voltage (the output voltage of the boosted-voltage power-supply circuit) have leakage resulted from manufacturing processes, it is possible that the potential of the output of the boosted-voltage power-supply circuit may not be increased sufficiently. In this case, for example, in the DRAM, even if the circuits causing the leakage are provided with redundant functions and designed so that such circuits can be isolated by reset operations upon activation of the internal circuit (power-on resets), such circuits cannot be reset and cannot operate properly.
Further, though it is possible to provide a plurality of boosted-voltage power-supply circuits for each circuit, it is not desirable because the number of elements for the boosted-voltage power-supply circuits and, thus, an area occupied by the elements are increased.
The conventional semiconductor integrated circuit device and its problems will be described in detail below with reference to the drawings.